TDA2030A Amplifier DIY Kit Schematic and soldering howto

This howto shows you the schematic of a popular TDA2030A amplifier DIY kit which is sold on eBay and other places.

After ordering the kit on eBay (search for “TDA2030A Audio Power Amplifier DIY Kit”) I received a version 1.0 PCB made by XY HI-FI with components and a short Chinese manual on what was needed to solder the kit in stereo mode (OCL) or in mono mode (BTL or bridge). Bridge mode doubles the output power and can be used to drive a sub-woofer loudspeaker. I cannot read Chinese and thus searched for an English manual but did not find any. I decided to reverse engineer the layout of the PCB to produce a schematic and better understand what I was building.

What I find worth noting is the way the designer routed the GND signals on the bottom of the PCB. They are all concentrated to where the power is supplied. This is needed because high power parts of the circuit could offset GND to a non 0 volt level and cause problems in the low power parts or other high power parts.

After carefully inspecting where all the traces go I came up with the following schematic. The schematic is mostly similar to the reference schematic in the TDA2030A datasheet. I used the one that can be found on www.st.com (Doc ID 1459 Rev 2). The PCB cleverly combines bridge mode (BTL) and stereo mode (OCL) by not soldering C9 or R4.

The schematic is ordered in different blocks. Power and rectification, audio input and volume control, the left and right amplifier.

The power and rectification block rectifies the double AC voltage and stabilizes it into 2 DC voltages. The negative and positive voltage. You can use a symmetric DC source to power the circuit and connect it directly to C1 and C2.

Audio input is connected to a double RCA connector and the volume is controlled by a 50K ohm stereo potentiometer. I guess it is logarithmic.

The left and right amplifier block amplify the audio coming from the stereo potentiometer and output it to the PCB connectors on the right.

* The schematic shows extra diodes (D1 to D4). These are not on the PCB but I added them to the schematic because the are recommended by the datasheet. There purpose is to protect the output of the TDA2030A amplifier to voltages larger than the positive and negative supply.

The TDA2030A amplifier chip is protected by a thermal shutdown mechanism and can be short-circuited making it safe to use.

Let go solder the PCB and components into a working amplifier!

5x resistor 22K Ohm 1%. Color code: red, red, black, red, brown.
Bend the legs (1cm spacing) and then solder R1, R3, R6, R7. Optionally R4. After soldering, cut of the excess legs sticking out of the back.R4 is only needed when you are going to drive 1 speaker in bridge mode. Do not solder when using the amplifier to drive 2 speakers in stereo mode.

3 terminal pcb screw connector.Solder it on the left side of the board next to the markings “AC GND AC”.
Note: solder it with the holes of the connector facing outward so you can later connect the power supply wires.

2x 2 terminal pcb screw connector.
Slide the connectors into each other in a way that you get a 4 terminal connector. Each terminal has a slot and ridge that interlock with its neighbor. Solder the now joined connector pair on the right side next to the markings “OUT GND GND OUT”.

4x 22uF 50V capacitor.
Solder C3, C4, C5, C6.
Note: the longer leg indicates the positive side of the capacitor and must be put into the hole marked with the “+”-sign.

1x stereo RCA audio connector.
Solder it on the pcb where it is marked “INPUT”.

1x 4A 600V bridge rectifier.
Solder “D”.
Note: the longer leg indicates the positive side of the rectifier and must be put into the top hole.

2x TDA2030A amplifier chip.
Solder IC1, IC2.
Note: keep in mind that you align the chips so that they can be mounted to the same heatsink. Maybe now is the time to prepare the heatsink and drill holes. You can mount the amplifier to the heatsink using the isolation pad, isolation bushing and screw.

2x capacitor 3300uF 25V.
Solder C1 and C2.
Note: Long leg in +.

You are now done! Go hookup 1 or 2 speakers, a power and audio source.
If you are using bridge mode, the 1 speaker must be connected only to the two “OUT” connections. Do no connect GND when using bridge mode.

I soldered one on BTL (bridge mode) so C9 is not mounted:

During testing I played some MP3 files and the TDA2030A amplifier sounded good. (for the amount payed it amplified perfect.) I did manage to blowup the left channel by driving a small Mabuchi motor with a diode connected in series. This translated into a very hot TDA2030A, curious about when the magic smoke got out I ramped up the power supply and waited. Only the solder on the TDA2030A started to melt, but no smoke. I guessÂ TDA2030A amplifiers do not run on magic smoke. Replacing the broken TDA2030A with a new one restored its function.

After the blown TDA2030A adventure I decided to mount the protection diodes. I guessed the voltage from a running motor feeding back into the amplifier is not something the TDA2030A can tolerate.

I mounted the diodes on the output, just as drawn in the schematic. The longer legs are protected by heat shrink tubes. On the left I connected the diodes to V- on capacitor C4. In the middle I scraped of some the blue solder resist and soldered the other pair of diodes to V+. The diodes are now here to protect the output from voltages greater then V- and V+.

Want to learn more about how the TDA2030A amplifier works? In the Youtube episode “SparkFun According to Pete 9-6-11″ the opamp is explained: http://youtu.be/OMJ9WGrRf6A

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What possesed you to hook a motor up to a audio circuit?!?! I am looking at
this board to replace a blown up altec lansing vs2121, that just stopped working the
other day. Nice post as it is only thing that explains it for a noob in this stuff.

I probably won’t get a feedback before I give this a go but I bought the same kit and using it for amplifier in a electromechanical racing game. The old amp was similar yet from 1969 . Two RCA jacks fed noise from the games mechanical parts. The first RCA plug is wired into a relay coil, it makes noise magnetically when the road motor is going faster , end of the motor has a metal wheel centered around a metal magnetic housing. The second rca jack is plugged into a pick up cartridge that receives noise from a crash sound (a simple metal plate getting hit by a solenoid plunger). I wired this up as a BTL connection I think that was correct. It only uses one speaker any suggestions before I plug this in?
Thanks
Chris

Hello,
I bought this board kit for a little amp to use for bench testing audio filters and effect boxes and whatever else i invent that makes sound. However I didn’t pay close enough attn to the power supply requirements of this board. Seems this takes a 12VAC as apposed to DC and nowhere – anywhere can I find any documentation that specifies what the current rate min/ max is. For example: I have a couple of wallwart AC power supplies rated at output of 12vac 850 mA, 12vac 500mA. These just dosent seem like they would have enough to power this.

I also bought the companion NE5532 Volume Tone control board kit 10 times pre-amp DIY For Audio Amplifier. This requires a 15VAC/ and once again I am unable to find current rating for these power supply requirements.

I am not familiar with AC circutry, mainly stick to 12VDC applications. but thought this would be a good project to start larning.

What I would like to do is build a dual power supply that will send 15v to the pre-amp and 12vac to the power amp.

One thing for sure is i’m not going to just plug these up to the wall, that sounds like suicide. And as much as I don’t fear death, the smoke and ash I leave behind just might hurt someone else. Not to mention the smell.

So If anyone has any bright ideas, precautions and next step learning, please drop me an email or something. You would be doing my whole Apt. complex a great service.

Hi, i hope you worked this out.
the NE5532 will work quite happily on +-12v (max +-22v, min +-5v) and the TDA2030 is fine on +-15v (max +-18v, min +-6v) so you could safely use 12vac or 15vac, did you notice on the datasheet that they run on rectified voltage……….. have you considered using 2 matching switch-mode DC power supplies in series as follows (+) (-+) (-) connecting 1 -to+ of the other making a centre tapped DC supply, you could effectively bypass the rectifier (unless you wanted to lose some voltage to the diodes) and go straight to the capacitors…… i’ve done this before as it was alot cheaper than buying a replacement centre-tap AC transformer, its like clipping 2 batteries together to double the voltage and the middle where they join is the centre tap for GND. (also works for AC or DC wire transformer PSU’s…. but get them matched for equal output)
12v 2a is quite cheap on ebay, TDA2030 is peak 3.5a output according to the datasheet. the LM1875 and also LM675 are both pin compatible but not really worth the upgrade for an extra 5w, as you’ll need to also upgrade the power supply (double-up), they take +-30v max and consume 4a…… interestingly, the datasheet for the LM675 shows how to make a split rail with 3a output….. so if you’re worried about using the home-made centre-tap from 2 power supplies, just use the full joined voltage (24v) and let the op-amp split it.
NEVER PLAY WITH MAINS VOLTAGE UNLESS YOU ABSOLUTELY KNOW WHAT YOU’RE DOING….. AND NEVER WHILE POWERED ON!!!!!!

Hi Wayne, that is actually a very smart suggestion. However, I only recommend it to those who understand the concept. Mixing up the positive and negative terminals have disastrous results when not done right the first try.

I bought a stereo kit from the BIG auction site and all I did was replace the 2200mf 25v power supply cap with a 35v one ’cause my ac transformer is an old 17v control transformer. the one i bought runs them on a single ended p/s. and i also added the 2 diodes that ST recommends. i play it on a very expensive pair of headphones and don’t need any surprises even though it’s cap coupled . i am impressed by the sound. i’m a class A tube freak and this little chip sounds pretty tubey!!! N1ACK Russ

I made it with R2 and R5 changed from 680 to 1500 ohms which reduces the gain by half and it sounds great, less noisy, and with a high input (CD, mixer etc) you don’t need that much gain. Maybe with a lower voltage input like phono preamp output you might want the full gain as on the specs.

Not sure if C3 and C6 should have also been changed but it seems not to matter.

Hi
Just bougt an readymade amp from china using this excact layout. I’m removing the C9 and installing the R4 to bridge it.
My questions are:
Do I use a stereo source? Or do I have to mix it to a mono before? If I mono it first, where do I input the signal?

hi, i have build some wat same circuit , but i am facing a problem that is when i increase the volume of both LHS & RHS a heavy knocking noise comes. but if i increase only LHS/RHS volume its sounds good.i want to hear in both channels . pls help

Hi
I built this. See my site under projects/Stereo Amplifier. Max voltage for the TX is 12v – 0 – 12 v This gives approx 18v – 0 – 18v (DC) This is the max the IC’s can “stand”. Due to the high current peaks a current rating of 2A is required. I used a 3A TX as I had it in stock. In a solid case the amp sounds very good.
Regards.
Eric

I have one of these kits on order from Amazon and plan to use it to research BTL config, initially with 2030’s then once I’m happy with it, uprating couple of single 2030 based 15W guitar practice amps to use BTL 2050’s into some higher powered Fane drivers, hopefully getting around 60W RMS into 8ohm for a SPL of around 115dB @ 1meter. Got a Fender squire 15 and a BEHRINGER V-TONE GM-108 both itching for new master volume that goes way past 10 for real!
If I learn anything useful I’ll follow up with further info here.

kit arrived from amazon.. was dissapointed in the 3300uF 25V caps as I’m expecting to want to go higher than 25V 0 25V when testing the TDA2050V chips. I found 4700uF 35V 105degC from maplin.co.uk code N97KF @ Â£1.15 each…. they JUST squeeze in.

I was wondering if I would be allowed to post a version of your schematic diagram thats had colours inverted and adjusted so it’s black on a white background as a customers picture on the amazon listing for this kit so future customers will see the diagram and this sites URL in the image?

Ok,Unfortunately I have already ordered 2 of the kits,Is there anything I can do to use them in Mono that might benefit the sound quality more,and still wire the speakers to both out’s on each amp board and single channel input.Initaily I wanted to use the 2 boards bridged ,Any thing I can do to doing it.

Ok, I will store these boards,until I learn more about parralell bridgeing.I fell in love with the sound of the 2030A I want to build a nice powerful example of one and something says to go this route.thank you though for the advice.maybe you will investigate this area too in the future.

I am not understanding,”R4 is only needed when you are going to drive 1 speaker in bridge mode. Do not solder when using the amplifier to drive 2 speakers in stereo mode”.does R4 left off or soldered for bridged mode.

I bought this board 1.5 years ago, in order to learn soldering. I soldered tha parts month ago, but i wasnt statisfied with the sound quality. I put it into a box, and have totally forgotten.
Today i found it, and i thought in the last months i learned enough electronics i’ll find the problem with this board..
My problem is.. I connect this amp board to 12V AC, everything ok.. Sound perfect.. after 10 second the sound quality starts to get lower and lower..
The voltage of cap which is directly connected to negative gets higher, the voltage of cap which is directly connected to positive gets lower..

The higher the voltage of “negative” connected cap, the bad the sound quality is.
If i break the the supply for a while everything will be ok for few seconds.
If i connect DC 12V to the caps, the symptoms are the same.
I double checked the connections, seems ok, i changed the capacitors, nothing changed.
Does anyone have any idea how i can solve this problem ?

if i “turn on” the amp (12V AC, after the recitifier ca. 16V DC) i can measure on both cap 8 volts. In this case the sound quality is perfect..
10 secs later one of cap has 5v the other one has 11v, and the sound is distorsed..
20 secs later one cap has 1.6v the another one is 14.4, and become the sound fully distorsed, and starts the amp “bummmming” (sorry for my terrible english :D)
i bought an NE 555 timer, because i wanted to learn and see how it works, and if i interrupts the power supply it works.. But i think its not normal behaviour.
Sadly i’m not an engineer, i started to build and learn electronics 2-3 months ago as a new hobby, therefore i cant imagine what could be the problem.

Have a look at the schematic on this page. It sounds like you connected a 2 wire transformer to the amplifier. Am I correct?
If that is the case, you need another transformer with 3 wires. Namely a 12V-0V-12V AC transformer. You then connect the center tap (0V) to GND. The other 2 into each AC input.